Tuning mechanism for multiband receivers



Jan. 20, 1942. H. SCHRODER. 2,270,772

TUNING MECHANISM FOR MULTIBAND RECEIVERS Filed July 16, 1940 l I M [I II F] O O 0 U1 OI e l COVER-P1197? IJIIIII ll I/I- Q e do 0 I \{1 1 o I l:

I E P o a he \i I Z w Q r A W -e Zinnentor Heinrich Ya/022(6) attorney Patented Jan. 20, 1942 TUNING MECHANISM FOR MULTIBAND RECEIVERS Heinrich Schrii'der, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphic in. b. H., Berlin, Germany, a corporation of Germany Application July 16, 1940, Serial No. 345,736 In Germany January 18, 1939 Claims.

The present invention relates to a switch device with arrester or detent points adapted to an apparatus in which an unbroken adjustment range is subdivided into several continuous ranges or bands being separated from one another by switch steps. Although the basic idea of the invention is generally applicable to the said purpose, it shall here be described, with a view to simplification of representation, to a special instance, that is, the tuning in arrester positions of an RF receiver apparatus comprising several wave-bands.

Arrangements of this nature are known in the prior art which work in such a way that inside a single wave band of an RF receiver apparatus, by the actuation of a single switch, it is possible to change directly from one signal frequency to a second or a third frequency. These systems known in the earlier art which work with mechanical arrester means are useful only for a single wave-band. When it is desired to distribute the various arrester positions over several wave bands it is necessary to eifect a change in the wave band together with the change-over of the various arrester points. For this purpose an assembly adapted to arrester switching in an RF receiver set operating with press-button control is known in the art in which, apart from the switching in of a circuit designed to cut in aircuit the motor to drive the rotary condenser (which works through the intermediary of a ro tary contact arrangement) switching over to the wave-band in which the desired signal wave is included to which the receiver set is to be adjusted automatically is effected simultaneously with the actuation of the press-button.

However, this known arrangement no longer satisfies practical requirements whenever the various arrester points are to be distributed at will and in any desired order or sequence over the various receiving bands.

Now, the object of the invention is an arrester switch device in which it is readily possible to eifect such exchange of the various arresters in any desired way at all. The basic idea of the arrangement of this invention is for switching in the proper wave band by positive action conjointly with arrester adjustment, a distributor arrangement consisting of two busbar systems or equivalent means are provided, the bars of one of these systems being connected with one of the contact arrangements operated by the various arrester adjusting means, while the bars of the other systems are connected with means causative of band changing.

The number of the bars forming one of the said systems is suitably chosen the same as the number of arresters to be adjusted, while the number of the bars of the other system must be adapted to the number of adjustment range or bands that are provided. Moreover, the bars of the two systems must be so mounted in relation to one another that each bar pertaining to one system is adapted to be electrically connected with each bar of the other system, say, by plugs.

The idea underlying the invention shall now be described in more detail by reference to the appended drawing which shows an exemplified embodiment of the invention. The assumption is made that in this embodiment the rotary condenser included in the signal receiving circuit is seated upon the shaft a which by the aid of a knob 9 may be driven at a suitable step-down ratio. Moreover mounted on the said shaft a, are disks )7, the number thereof corresponding to the number of arrester points that are required. Each of the said disks has a notch b in which latches or pawls 0 may engage as the disk is rotated. Posteriorly of each of these latch members c is arranged a plug which controls a contact device at in such a way that the contacts d are closed as soon as the latch c has engaged its corresponding notch b of disk h. Now, the various contacts are in parallel connection to a distributor assembly e comprising two busbar systems. Both of the latter are disposed at right angles to each other and they are confined inside a lockable case. While the bars of one of the said systems are each united with the corresponding contacts d, the bars of the respective other system are brought to solenoids f. The number of the latter corresponds to the number of wave bands provided in the receiver set. As known in the art, each of the said windings when energized cuts in circuit one or more coils n, depending upon the number of tuned circuits provided in the receiver, each set of such coils being designed to tune the receiver to a different waveband.

Now, the bars of the two busbar systems are disposed in superposed relation such that each bar belonging to one of the systems may be conductively connected with any one of the bars of the other system. For this purpose are provided a number of plugs is adapted to be inserted in openings corresponding thereto. With a given arrester being operated, to ascertain which one is involved, annunciator means m are provided which are automatically actuated by the particular arrester latch which is operated.

Now, the operation of the arrangement according to the invention is as follows: By turning the knob g the rotary condenser is rotated together with the disks h mounted upon the shaft a. Upon a latch 0 coming to engage with a notch 2) formed in one of the disks it there appears the corresponding annunciator or indicator element m which indicates engagement of a particular arrester. However, in addition the pair of contacts d disposed posteriorly of the latch or pawl c is closed so that by way of the busbar system 6 a current is made, that is to say, this current will be caused to fiow through the plug it which happens to be inserted and the solenoid j which corresponds thereto. By turning of the knob g, as will thus be seen, the rotary condenser seated on the shaft 11 is caused to assume an arrester position, while in addition as a result of energization of the corresponding solenoid the Wave band is automatically switched in, in which the selected arrester position happens to be included.

Coordination of the arresters and the wave bands is effected solely by the introduction of plugs in corresponding holes of the distributor system c, the latter being closed after an adjustment has been made. It is thus feasible to coordinate to the various arrester positions waves pertaining to any desired wave band on the basis of random exchangeability.

Another advantage of the invention resides in its greater speed of adjustment or tuning of a receiver set thus operated for the reason that the distinct knob usually provided for the wave band change is dispensed with and since hunting through all of the bands is no longer required.

I claim:

1. In a multi-band receiver, a variable tuning reactor, a plurality of fixed reactors each corresponding to one of a plurality of wave bands to which the receiver is adapted to respond, means for adjusting the tuning reactor, a plurality of discs, each having a peripheral notch, movable with and under control of said adjusting means, separate means cooperating with said discs and adapted to engage the peripheral notches for arresting said tuning reactor at predetermined positions, and means including switch means actuated by the arrester means at said predetermined positions to select a predetermined one of the fixed reactors.

2. In a multi-band receiver, the invention as defined in claim 1, wherein the tuning reactor arresting means have associated therewith mechanism for visually indicating the particular wave band in operation.

3. In a multi-band receiver, a variable tuning reactor, a plurality of fixed reactors each corresponding to one of a plurality of wave bands to which the receiver is adapted to respond, means for adjusting the tuning reactor, a plurality of members under control of said adjusting means each adapted to arrest said tuning reactor at one of a plurality of predetermined positions, a switch associated with each arresting member, a first set of bus-bars equal to the number of switches connected respectively to a contact of said switches, a second set of bus-bars equal to the number of fixed reactors connected respectively to corresponding terminals of a set of reactor relays, said sets of bus-bars being so constructed and arranged that by means of contactors selected ones of the first set and selected ones of the second set are electrically connected together, and a source of power connected between the other switch contacts and the other relay terminals, the arrangement being such that at any arrested position of adjustment of the variable tuning reactor, the associated switch is closed to complete a circuit through a pair of bus-bars, one in each set, thereby energizing the appropriate reactor relay.

4. In a multi-band receiver in accordance with the invention defined in claim 3, wherein the tuning reactor arresting members comprise a plurality of discs, each having a peripheral notch and each switch associated with an arresting member is provided with means to engage said notch whereby the tuning reactor is stopped at a predetermined position.

5. In a multi-band receiver in accordance with the invention defined in claim 3, wherein the tuning reactor arresting members comprise a plurality of discs, each having a peripheral notch and each switch associated with an arresting member is provided with means to engage said notch whereby the tuning reactor is stopped at a predetermined position, and mechanism associated with the notch engaging means for visually indicating the particular wave band in operation.

HEINRICH scHRoDER. 

